San Francisco

Climate: Summer doesn't necessarily feel very summer-like in San Francisco, where the average high in July is 70.

Advantage: With its sparkle and international cachet, San Francisco, unlike Chicago in the 2016 race, wouldn't have to be "introduced" to the world.

Obstacle: Though San Francisco itself is compact - or maybe because it's compact - these games have the potential to sprawl to Oakland, Santa Clara, San Jose and beyond. These are not quick trips.

Los Angeles

Venues: The only city of the four to have hosted an Olympics (1932, 1984), Los Angeles hopes to renovate the Coliseum. (A new NFL stadium might be in place by then, too.) Downtown Los Angeles would host about half the events, and the organizing committee says it can transport about 80 percent of spectators via an expanded metro rail system and other public transportation.

Climate: Temperatures in July and August hover between 75 and 85, depending on how close to the water you are. After Beijing, it will be hard to complain about smog, but it does exist in Los Angeles.

Advantages: They've done this before and those in the IOC with long memories certainly credit Los Angeles for reviving the Olympic movement with its successful 1984 Games.

Obstacles: The chance that it could feel like 40 separate events being held over a sprawling cityscape. Though London set the precedent by hosting three Olympics, the IOC might not want to make that a habit.

Boston

Venues: Gillette Stadium, Boston Garden, Fenway Park, the Boston Marathon course. These games would almost certainly be spread around New England. But where does the main stadium go?

Climate: Average high around 80 degrees in July and August. It rains and can get muggy, but nothing to prevent the Games from taking place.

Advantages: Hard to find a city with a better sense of sports than Boston. Mitt Romney, largely credited for saving the Salt Lake City Games, will probably be involved.

Obstacles: Times have changed, but those looking to pick on Boston's ability to deliver on a big project (and yes, negative campaigning is part of this game) will find the city to be an easy target. Just go back to "The Big Dig" - that disorganized, delayed and massively over-budget tunnel project through the city.

Washington

Venues: Including Camden Yards and M&T Bank Stadium in Baltimore and FedEx Field in Landover, Md., the D.C. area claims to have the most venues in a 40-mile range in America. A new stadium is due to be built on the site of the old RFK Stadium.

Climate: The average high in July is 87 - 2 degrees cooler than Atlanta.

Advantages: Many venues are built and ready to go. Hard to question Washington's ability to put on a big show.

Obstacles: Q: What's the capital of Brazil? (Hint: It's not Rio). A: Brasilia. The point: Just because it's a capital city doesn't mean it resonates worldwide the way, say, Rome or Paris might.